Radio antennas are critical components of all radio equipment, and are used in radio broadcasting, broadcast television, two-way radio, communication receivers, radar, cell phones, satellite communications and other devices. A radio antenna is an array of conductors electrically connected to a receiver or transmitter, which provides an interface between radio frequency (RF) waves propagating through space and electrical currents moving in the conductors to the transmitter or receiver. In transmission mode, the radio transmitter supplies an electric current to antenna terminals, and the antenna radiates the energy from the current as electromagnetic waves (radio waves). In reception mode, the antenna intercepts some of the power of an electromagnetic wave in order to produce an electric current at the antenna terminals, which is applied to a receiver for amplification.
One type of radio antenna is a phased array line feed antenna. The phased array lined feed antenna is typically optimized for continuous, electronic beam steering in association with or without a spherical reflector. An example suitable application for the phased array line feed antenna is space applications. For applications that require a narrow RF beam, complex driving electronics are needed to control the phased array line feed antenna. For example, phase shifters can be utilized to provide the narrow RF beam. But phase shifters tend to be lossy, which requires additional power amplifiers for both receiving and transmitting.
As a result, adapting the phased array line feed antenna for a narrow RF beam application is expensive. In applications where a narrow beam is desired, such as 5G applications, both the narrow RF beam as well as a beam steering function is desirable. Unfortunately, implementing both a narrow RF beam and a beam steering function in a cost-effective manner is difficult in radio antennas, such as the phased array line feed antenna.